1. Field of the Invention
The present invention relates to a startup procedure, and in particular to a startup procedure for reading a disc without updating the focus servo parameter and the track information in the memory.
2. Description of the Related Art
Generally speaking, conventional optical discs can be CD-ROM, CD-R or CD-RW. Since CD-ROM is the oldest format, data storage therein is slightly different from CD-R and CD-RW.
Referring to FIG. 1a and FIG. 1b, storage format of a conventional CD-ROM is shown. In general, Spiral track of disc 100 is distributed outward from the inner circle. As shown in FIG. 1b, the track of a disc is represented as a straight line. Data distribution can be divided into lead-in zone 102, data zone 104 and lead-out zone 106. These three zones form a session 110, wherein lead-in zone 102 is located in the inner circle of the spiral track, and lead-out zone 106 is located in the outer circle of the spiral track. Between the lead-in zone 102 and the lead-out zone 106 is data zone 104. Conventional CD-ROM discs support multi-session format, within which another session 120, comprising lead-in zone 112, data zone 114 and lead-out zone 116, can be stored on the same conventional disc.
In general, table of contents, herein TOC, in the lead-in zone stores the start addresses of the data on each track of the data zone. Therefore, the optical pick up head must be moved to TOC to retrieve the start addresses of the data in each track in advance so that it can retrieve data from the data zone.
As shown in FIG. 2, the spiral track of a conventional CD-R or CD-RW is represented in a straight line. An additional program memory area 200, hereafter referred to as the PMA 200, is in the area of the innermost circle in CD-R or CD-RW unlike the format of CD-ROM. In addition to TOC, other related information of the data zone is included in the PMA, for example, the end addresses of each track, and others. Thus, the data distribution of conventional CD-R and CD-RW is PMA 200 in the innermost circle, followed by session 210, up to session 220. Each session comprises a lead-in zone, data zone and lead-out zone. For example, session 210 comprises lead-in zone 212, data zone 214, lead-out zone 216, and session 220 comprises lead-in zone 222, data zone 224 and lead-out zone 226. In order to support the CD-ROM, TOC is included in the lead-in zone.
In general, there are several writing modes in which CD burners record CD-R or CD-RW.
Track at once, hereafter referred to as TAO, is a recording scheme in which, for each writing, the data of only one track is written in the data zone, information relating to the written data is saved in PMA, and the start addresses of all tracks are recorded in TOC in order to be compatible with the CD-ROM format.
Session at once, hereafter referred to as the SAO, is a recording scheme in which, for each writing, all the data of a session is written in a disc, i.e. lead-in zone, data zone and lead-out zone are written. As well, all the information of the session is written into PMA, and the TOC of the lead-in zone is, naturally, written commensurate with entire session.
Due to the ongoing advances of recording technique, the recording speed of CD burners has achieved 52× speed, taking as little as 2 minutes to record a CD-R or CD-RW, compared to previous CD burners with average recording times of 10 minutes.
When recording in the SAO scheme, the chipset of the CD burner must control a memory (usually a dynamic random access memory, DRAM) to store all track information including all information of the TOC and PMA. Therefore, during writing, the chipset acquires and reassembles the corresponding information when data is recording on the disc before writing it to TOC or PMA. After the disc writing procedure is finished, all information related to the PMA of the disc can be acquired from the memory and then write on the PMA of disc.
Generally, the recording operation includes writing and reading procedures. In a SAO scheme for example, writing procedure takes place when the PMA and all sessions are written unto a disc, and then reading procedure immediately follows.
In conventional recording operations, a startup procedure should be performed firstly at the beginning of reading procedure. At the same time, the disc is re-rotated, and the CD burner performs servo focus parameter searching again for storing the focus servo parameter in the memory. Next, track information is re-read again within the PMA and TOC and then memory-is updated by the chipset with the read track information. Then, the CD burner retrieves the recorded data in data zone using the track information.
The reading procedure of the CD burner is then finished. The Startup procedure, however, includes rotating the disc, searching servo focus parameter, and reading track information, each of which requires about 10 to 30 seconds. In a conventional CD burner with very low burning speed, time required by the startup procedure is much shorter than the total time required by writing procedure. It is not necessary to consider the wasting time of the startup procedure. However, in modern CD burner, it seems waste of time in startup procedure because of the short time spent in writing procedure. Hence, it is necessary to save time required by startup procedure for reading procedure.